Electrical relay



March 16 1926. 1,577,231

.S. c. HOFMANN ELECTRICAL RELAY Filed Nov. 21, 1924 INVENTOR I i f-Ma 5w ATTORNEY UNITED ;srarss Patented Mar. 16, 1926.

SEBASTIAN o. HorMAivn, becnmmemizmpis ELECTRICAL RELAY.

Application filed November 21 1924. Serial No. 751,230.

To all whom it may concern:

Be it known'that I, SEBASTIAN C. Hor- MANN, a citizen of the UnitedStates, residing at Champaign, in the county of'Champaign and State ofIllinois, have invented certain new and useful Improvements 'in.Electrical Relays, of which the following is a specification.

My invention relates to electrical relays, and particularly toalternating current induction motor relays of the vane type One featureof my invention. is the provision, in relaysof this type, of aconstruction which'will prevent the vane from occupying an intermediateposition wherein ljoth the front and the back contacts are open when therelay is under-energized.

I will describe one form of relay embodying my invention, and will thenpoint out thenovel features thereof in claims.

In the accompanying drawing, Fig. 1 is a view showing in front elevationone form of relay embodying my invention. Fig. 2 is a top plan view ofthe electromagnetic elements of the relay shown in Fig. 1.

Referring to the drawing, the relay comprises a vane 2 pivotally mountedat 2 and biased by its own weight to the position in which it is shownin the drawing wherein it rests against a stop 3. The vane swingsbetween the poles of a U-shaped magnetizable core 4 provided with awinding 5 which as here shown is in two sections one being on each legof the core. The upper portion of each pole is surrounded with a copperferrule 6 whereby when the winding 5 is supplied with alternatingcurrent the vane 2 is subjected to a shifting magnetic field whichswings the vane in clockwise direction against the force of gravityuntil it engages a front stop 7 The vane 2 controls a back contact 8 anda front contact 9 in the usual manner, that is, through the medium of arocker member 11, an arm 12 attached to member 11, and a link 1?)connecting the arm 12 with a crank 14 on the shaft 2*. When the relay isdeenergized so that the vane is in its biased or lower position, theback contact 8 is closed and the front contact 9 is open; whereas, whenthe relay is energized so that the vane is shifted to its upper positionagainst the front stop 7, the back contact 8 is open and the frontcontact 9 is closed. The contact arrangement is such that wher the relaybecomes de-energ'ized the front contact '9 opens before the backcontact'8 closes, and conversely, when the relay becomes energized theback contact 8 opens before the'front contact 9 closes,'

Relays of the type shown in the drawing are so well known inthe art'ofrailway signaling that a moredetailed descriptionv of the structure isunnecessary; I have found that when the current in'jwinding 5 drops to avalue considerably below'normal, that-is, when the'relay isunder-energized, thevan'e 2 may drop away from thej'front 'stop'7 andassume a position of rest jwherein gboth the'frontcontact'S) and theback-contact 8 areopen. "This is undesi'rable,'-and I have found that itmay be prevented by cutting a slot 10 in the vane 2. The size of thisslot will depend on the size and characteristics of the relay; for arelay of the size shown in the drawing the slot is preferably about inchby 1 inches in size, the long dimension being radial with respect to thepivotal axis 2 of the vane, and the slot is preferably so located thatit substantially registers with the ferrules 6 when the vane is in itslowest position. This slot causes the relay to have positive pickup andrelease voltages, so that there is no voltage at which the vane willremain in an intermediate position wherein the front and back contactsare both open.

Although I have herein shown and described only one form of relayembodying my invention, it is understood that various changes andmodifications may be made therein within the scope of the appendedclaims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. An induction motor relay comprising a vane, and front and backcontacts controlled by said vane, said vane being provided with a singleslot whereby either said front or said back contact will be closed whenthe relay is under-energized.

2. A relay comprising a winding which is at times supplied withalternating current, a vane inductively operated by alternating currentin said winding, a front contact and a back contact controlled by saidvane and closed respectively when said winding is energized andde-energized, the front contact being arranged to open before the backcontact closes when the winding becomes, tie-energized and vice-versa,said vane being provided With a slot to prevent the Vane occupying aposition wherein both contacts are operr when-said -'winding-- is*under-energized.

3. An induction motor relay comprising by said vane-andso arranged; thatthe front I contact opens before the. backscontact closes when: therelay becomes de-energized and vice-versa, said vanebeingzprovidedwith aslot approximately. onerhalfinch .by one and one-eighth inches in sizeto, prevent the vane occupying, a: position wherein both contacts areopen when 'the relay is underwenergized.

5. An induction motor itj-c'd fprisi ig" a vane, and front and backcontacts V trolled by said vane, said vane being ro -vidd-with-a singleslbhapproximately onehalf inch by one and one-eighth inches in size toprevent the vane from occupying a position wherein both .said contactsare open when the relay is under-energized.

I 6. A relay comprising a corehaving. confronting poles, a ferrulesurrounding a portion of each pole, a winding for 'said'core, avanemounted to swingbetween said poles, and front and back contactscontrolled by said vane and so arranged that the-front 7 contact opensbefore the back contact closes when the relay becomes dc-energized andvice-versa, said vane being provided with a slot approximatelyone-.lialf-inch one and one-eighth inches in size. located tosubstantially register with said ferrules when the relay isde-energizedl Intestimony whereof I aflix my signature.

SEBASTIAN C. HQFMANN.

